The present invention relates in general to food merchandising equipment and pertains, more particularly, to food merchandisers of the type used in grocery stores, convenience stores and any other stores in which food may be offered for purchase or consumption. The food merchandiser of this invention is an improvement over the conventional merchandiser used to offer hot food for consumption or purchase.
With the conventional food merchandiser it is generally necessary to provide a heat source based upon steam, hot water or conventional electrical heating elements. Conventional heating elements include Cal-Rod-type elements used in numerous commercial and industrial applications and the heat energy supplied by these elements is sometimes referred to as short wave energy.
These conventional heat sources are constructed in a way that maintenance and clean-up of the steam and hot water sources are difficult and can accelerate deterioration of the components of the merchandiser. Another drawback associated with the conventional electrical heating elements is the creation of hot spots that ruin food displayed in the merchandiser due to hot spots created by the electrical heating elements.
Some conventional hot food merchandisers use electrical heating technology in which circular cross-section heating element rods loop underneath a well. A rod or combination of rods are controlled by a rheostat that lowers rod temperature by reducing voltage by means of a variable resistor which changes the current through the rods.
The heat energy generated by conventional electrical heat elements is intense and doesn""t disperse evenly through the material on which the food rests. The heat generated by the conventional electrical heat sources tends to concentrate in spots on the heat-conducting tiles or sheets on which the food or food containers rest and the lack of heat dispersion creates an undesirable, uneven heat distribution that can result in continued cooking and burning of the product directly over one or more heating rods.
Thus, localized areas of intense heat and temperature can result in food spoilage and wasted electrical energy. Local hot spots are not desired for food display or storage and a rod or rods use excess energy to maintain the edges of the well at the minimum temperature while the portion of the well at and close to the location of the rod is overheated.
Another drawback associated with the aforementioned electrical heating elements is the use of conventional rheostats and associated circuitry to control the energy output of these electrical heating elements. Prior to this invention, the combination of these conventional controls and their equivalents has not provided a desired heat supply and or desired dispersion of the heat, resulting in a hot food merchandiser or other form of display apparatus that may tend to continue to cook the food therein rather than merely keep it warm.
The present invention includes the unique combination of a proportional controller to maintain an even output from a long wave energy heat source. Conventional proportional controllers also have drawbacks associated with their inability to satisfactorily handle noise typically found on a primary power line with the use of conventional filters, grounding configurations, or circuits to chop or otherwise modify primary line noise. In addition, conventional proportional controllers do not always reduce voltage in a satisfactory or adequate fashion.
Accordingly, it is an object of this invention to provide an improved merchandising or display case that is adapted to maintain food within a predetermined temperature range. With the merchandiser, heat source and controller of this invention heat distribution is more even and power consumption is reduced when compared to conventional equipment constructed for the same purpose.
Another object of this invention is to provide an improved hot food display case or merchandiser apparatus constructed to provide more uniform heat distribution to thus provide more uniform heating of food within case or apparatus.
A further object of this invention is to provide a hot food display case or merchandiser apparatus that is adapted for the uniformed, controlled heating of any food placed on a heat source within the case or apparatus to thereby substantially reduce any over-cooking of the food placed on the heat source.
Still another object of this invention is to provide a hot food display case or merchandiser apparatus that may provide heat from both above and below food placed within the case of apparatus. The case or apparatus of this invention may have an upper heat source comprised of a material providing a long wave energy heat source.
Still a further object of this invention is to provide an improved case or apparatus that is adapted for uniform operation of the heat source and the heat source controller. The case or apparatus of this invention is characterized by a improved uniformity in the source of heat and control of the heat output from the heat source.
Another object of this invention is to provide an improved hot food display case or merchandiser apparatus that includes a controller incorporating primary line noise control and suitable voltage reduction without an unnecessary feedback loop.
A further object of this invention is to provide an improved hot food display case or merchandiser apparatus that incorporates design flexibility as to heat source location, control and case or apparatus configuration and appearance. The construction of this invention allows for a variety of heat source locations and associated controls, that is, the number of hot xe2x80x9cwellsxe2x80x9d may be selected to suit the application (e.g., grocery store, delicatessen, convenience food store), as illustrated in the accompanying drawing figures.
Still another object of this invention is to provide solid state percentage controller in combination with a poured heat element. This combination uses less energy as the entire heat element incorporated in this invention is alternately energized and de-energized and maintains a uniform temperature without the hot spots that can be created with conventional heating rod technology.
To accomplish the foregoing and other objects of this invention there is provided a hot food display case or merchandiser apparatus, hereinafter xe2x80x9cdisplay casexe2x80x9d for controlling and maintaining food temperature within a pre-selected temperature range.
The display case comprises a case with side members or panels, toe kicks, typically front and back, and an upper support structure that provides support for one or more sliding doors, lights, and an upper heating element. The case includes a well or wells that receive a lower heating element material. A percentage controller described elsewhere in this application controls the temperature of the wells.
The display case of this invention is preferably adapted for use as a heated or hot food display case. The drawing figures contained herein illustrate the ornamental design of preferred embodiments of this invention.
While this invention is particularly adapted for use with heated display cases, it will be understood that the display cases of this invention may also include conventional refrigeration apparatus and the drawing figures reflect embodiments of this invention incorporating the refrigeration equipment.
In the disclosed embodiments described herein, there are provided display cases with three or more heated wells and an upper heating element are incorporated into this invention.
There is also provided a percentage controller that comprises one ore more controllers for each display case. The description of the percentage controller invention includes one or more percentage controller power panel switches and a preferred embodiment of the percentage controller schematic from which one skilled in the art will readily understand this invention.
In this disclosed embodiment described herein, there are provided a controller for each heated well and upper heated element for the display cases described and shown herein. It will thereafter be understood that the percentage controller of this invention is readily adapted to other AC voltage control applications, and is not limited to use with the display case embodiment described, shown and claimed.
These and other objects and features of this invention will be better understood and appreciated from the following detailed description of preferred embodiments thereof, selected for purposes of illustration and shown in the accompanying drawings.